Degree minutes and seconds changed into Decimal?

How do I change a the following into decimal form? 23 deg. 30' 15"

1 degree = 60 minutes
1 minute = 60 seconds

23deg 30min 15 sec
= 23 deg +(30/60) +(15/60/60)
= 23 +0.5 +0.00417
= 23.50417 deg ----answer.